This invention relates to a hydraulic fluid filter assembly and more particularly to a mounting device for positioning a filter element in a predetermined location within the filter housing as well as a reversible, poppet type bypass valve which is usable with the assembly in either forward or reverse flow filter embodiments.
Filter assemblies of a generally tubular configuration having a removable end wall are well-known in this art and provide the advantage of easy access to the interior of the filter housing for replacement of the filter element therein or for other servicing reasons. It is typical of devices of this type, however, that one end of the filter element is supported on a central structural support, which also might support a bypass valve therewith, the latter being used for routing fluid around the filter element upon a build-up of contaminants therein. Such typical structure is depicted in U.S. Pat. No. 3,618,776 and it is apparent in such arrangement that there is little tolerance for variations in axial dimensions and that the central part of the filter element is obstructed to a degree by the central mounting posts. Further, a machined head is used as the closure member, this being a relatively heavy and expensive structure which is machined to fit the housing and which is tapped for receipt of the central support post.
A different approach to mounting the filter element in a filter housing is shown in U.S. Pat. No. 3,640,390 wherein a spider assembly is employed at one end of a filter element which together with a central compression spring at the other end serves to support the element within the filter housing. In this arrangement the entire filter housing is supported on and positioned relative to a threaded central fluid port. The position of the filter element with respect to the housing is substantially fixed and is dependent upon support provided at the inside diameter of the filter element. The support structure in this instance also houses a bypass valve therein and is removed with the filter element for replacement purposes.
Still another filter assembly of the removable end wall type is shown in drawing No. D-2692 of Schroeder Brothers Corporation, which shows a spring biased mount which engages the inside diameter of the filter element and supports a bypass valve therewith. Sealing engagement with the filter element is made at the axial ends thereof and a relatively cumbersome head casting structure is employed.
A still further showing of a filter assembly with removable end structure is that of U.S. Pat. No. 4,142,973, showing as well a bypass valve of a particular configuration for providing an electrical indication of a valve open condition, thus indicating a contaminated filter element. In this arrangement the bypass valve is radially oriented in a head casting of the filter assembly at a position in line with the inlet port. The filter assembly is apparently designed only for unidirectional fluid flow.